1. Field of the Invention
The present invention relates to a stirring method. More particularly, the present invention relates to a stirring method comprising moving particles consisting of or comprising a magnetic material under the influences of a rotating magnetic field to prominently promote the transfer of substances and/or heat in liquid-gas phases, liquid-liquid phases, liquid-solid phases or in liquids.
2. Description of the Prior Art
In the industrial fields, there are many operations requiring the transfer of substances and/or heat between two fluid phases including a liquid, for example, gas-liquid phases, liquid-liquid phases or solid-liquid phases. It is well known that in these operations, the resistance against the transfer of substances and/or heat is present mainly in the vicinity of the interface between two phases. In order to decrease such resistance and enhance the transfer rate between the two phases, it is necessary to cause a disturbance in the interface between the two phases. However, there has not been developed any method for effectively causing a disturbance in the interface between the two phases in the vicinity thereof. Therefore, a method for stirring the liquid entirely has heretofore been adopted. Stirring the entire liquid is effective for improving the transfer rate in the liquid, but the effect of increasing the transfer rate in the interface between the two phases and in the vicinity thereof is not so prominent as compared with consumption of stirring power.
Furthermore, there has not been developed an effective stirring method to be applied to the case where in a system comprising at least two liquid layers differing in density, one specific liquid layer alone should be selectively stirred.
Still further, there has not been developed an effective stirring method to be applied to the case where in conducting a reaction while moving a liquid in a tank or column by piston flow, a specific layer alone should be selectively stirred.
In the industrial fields, there are many operations requiring transfer of substances and/or heat in solid-liquid phases, gas-solid phases or liquid-liquid phases, such as reactions using a solid catalyst or immobilized enzyme or dissolution of solid or adsorption.
In these operations, resistance against the transfer of substances and/or heat is present mainly in the vicinity of the interface between the particulate solid and the fluid, as is well known in the art. In order to decrease this resistance and enhance the transfer rate between the two phases, there has heretofore been adopted a method in which only the fluid is entirely stirred. Stirring the entire fluid is effective for increasing the transfer rate in the fluid, but the effect on improving the transfer rate between the phase of fine particles and the fluid phase is not so prominent as compared with consumption of the stirring power.